Inventions incorporating rotating horizontal disc cultivators are not new. Examples of patents incorporating such disc cultivators include the following U.S. Pat. No. 459,971 to Arnett; No. 1,370,774 to Abernathy; No. 1,158,906 to Eccles; and No. 556,075 to Whipple. These patents generally show a horizontal disc structure either attached to a shaft or integral therewith for working the soil. The disc and shaft structures rotate about an upstanding axis.
Prior art horizontal disc cultivators often employed no bearings or a journal bearing system which allowed dirt to easily infiltrate into the bearing. The abrasive dirt caused fast wearing of the bearings, supporting upright shaft, or the implement frame itself. When the bearings or frame became worn, the disc tended to vibrate excessively, either from side to side or back and forth.
Another problem associated with prior art horizontal disc cultivators was the buildup of straw, weeds and other debris about the disc shaft or supporting framework. To help alleviate this problem, a number of inventions were made which incorporate scrapers to clean the disc or the disc and disc shaft simultaneously. Examples of inventions incorporating such scrapers include U.S. Pat. No. 673,304 to Tharp; and U.S. Pat. No. 1,105,570 to Lea.
The scraper approach may have been effective at removing the soil from the disc and shaft, but the scraper was very prone to collect weeds and straw. When the buildup of weeds and straw became sufficiently large, it was necessary for the farmer to stop the implement, get off and clean the disc assembly. The problem of accumulated debris has continued until this invention with none of the prior art horizontal disc cultivators being satisfactory in their ability to operate for long periods of time without collecting accumulations of straw and debris.
The prior art also includes U.S. Pat. No. 4,294,181 to Smith. The Smith patent shows a subsoil horizontal disc cultivator having supporting frames for the discs which extend very near to the ground. The disc shaft was made hollow thereby allowing seed and fertilizer to be dropped through the shaft and into the ground while simultaneously cultivating the soil. This arrangement suffered from the problem of collecting straw, debris, and weeds as it was pulled through the field. West German Pat. No. 2,651,877 and Australian Pat. No. 124,777 also show rotatable, horizontal disc cultivators having hollow shafts through which fertilizer or seed could be fed into the ground while simultaneously cultivating the soil.
The current invention is directed to solving the limitations of the prior art as discussed above. In particular, the invention provides a rotatable, horizontal disc cultivator which can be drug through the soil without accumulating weeds and straw. The invention also provides a very rigid and durable bearing support for the rotatable disc and its supporting shaft while also keeping the bearing system protected from dust. Other advantages and objectives of the invention will be apparent from the description given below.